1. Field of the Invention
This invention relates to automatic clothes drying machines and more particularly to a method and apparatus for operation of such a machine at dual energy input levels.
2. Description of the Prior Art
Operation of clothes drying appliances at different temperatures during a drying cycle is known in the art. A high level of temperature is generally employed for fast drying and a lower level is provided for efficient drying, utilized less power input. When dual heat operation is utilized, such as in U.S. Pat. Nos. 3,508,340 and 2,863,224, the period of high heat operation is followed by a period of low heat operation. It is the teaching of the art that such a sequence is to be followed to provide relatively efficient drying followed by gradually cooling down of the dryer so that a relatively low temperature level is present at the end of the cycle. However, the most efficient drying is shown in U.S. Pat. No. 3,116,983 where a low heat 120 volt input is utilized over the entire cycle.
Many machine washable clothes currently available are chemically treated to exhibit permanent press charcteristics. The permanent press process does not prevent the clothes from wrinkling, but rather acts to smooth out wrinkles in the clothes when the clothes are elevated to a certain temperature. Thus, when permanent press clothes are dried in a conventional dryer having a cycle of low heat input only, the clothes generally are not elevated to a sufficiently high temperature to activate the de-wrinkling properties of the permanent press treatment. Since with a low heat input constituting the entire cycle of operation there is generally not a sufficient temperature rise to activate the permanent press treatment, the permanent press clothes emerge from such a conventional low heat drying cycle with wrinkles.